text:
What records should a CFI keep to prove they took due care in the quality of their instruction?
I know there has been some cases where a flight instructor is sued after a current or former student does something that gets themselves (the student) killed or causes damage.
I know that there have been cases where a flight instructor has been acquitted by proving that they took due care in their flight instruction, and the accident was not a result of poor instruction.
What specifically would a prudent flight instructor do to ensure they are keeping detailed enough records to prove that they are providing adequate instruction and that a resulting accident would not be due to poor instruction?
What are the records a CFI is legally required to keep, and what are the records they should keep in addition to that?
This question is in context of CFIs in the United States.

Have a well defined syllabus, and then a daily activity sheet where you write down the lesson you did, the time it took, and how the student performed. If anything peculiar happens, make a note.
Have a well-written lesson binder too. Even if you don't need to use the binder to teach a lesson (like steep turns, that's not really much of a ground lesson), have it in there anyway to show that you know what you're talking about. If you have a page that only says "Teach steep turns" and a lawyer gets a hold of it, there's nothing to prove that you actually know how to teach steep turns.
AS for legally required records:

You must sign the logbook of anyone you have given flight or ground training.
You must maintain a record of the following:

The date and name of each person whose logbook/student pilot certificate you endorse for solo flight privileges (I keep a record of every endorsement).
The date and name of each person you endorse for a knowledge/practical test, and the kind, date, and result of the test.

You must keep the records for at least 3 years.

How much detail would you recommend for the lesson plans in the binder? Going with the steep turns example, is it enough to say something like "Ref. FAA Airplane Flying Handbook, 9-1", or should the maneuver objectives, parameters (aircraft configuration, airspeed, bank angle, etc.), & performance requirements (from the PTS) be spelled out explicitly?

@voretaq7 - I'd spell it out. It's a small bit of insurance that takes 15 minutes and lasts forever. Looks better during your checkride too.

Our 141 school keeps records digitally, but before that we used curriculum binders.  Each flight in the course had its own lesson plan listing:

The planned lesson time
The actual lesson time
The elements or maneuvers to be accomplished
What level of proficiency the student would need to demonstrate on each element in order to be considered satisfactory
A space for the student's actual proficiency level per element
A space for remarks

Once the flight was complete, after filling out the logbook, both the instructor and student would sign the lesson sheet.  When everything in the binder was PTS or better, the student could be endorsed for the checkride.
As to the second half of your question, I just copied this directly from StallSpin's excellent answer.

AS for legally required records:

You must sign the logbook of anyone you have given flight or ground training.
You must maintain a record of the following:

The date and name of each person whose logbook/student pilot certificate you endorse for solo flight privileges (I keep a record of
  every endorsement).
The date and name of each person you endorse for a knowledge/practical test, and the kind, date, and result of the test.

You must keep the records for at least 3 years.

Even though the minimum is 3 years, I keep the records forever.

What do you use to keep the records digitally? Is there a specific software program you use or just a bunch of Word/Excel files?

@Canuk - http://www.talon-systems.com/


text:
Can I land a helicopter anywhere?
If I own a helicopter and am appropriately rated, can I land the helicopter anywhere that isn't private property, and is a safe place to land (clear of obstructions, appropriate surface, etc.)?
My question is specifically about the regulatory requirements to land a helicopter off-airport in the United States.

Per §91.119 of the FARs, yes. That said, you can't just find an open field-there may be local/state regulations regarding helicopter operations.
14 CFR 91.119:

(1) A helicopter may be operated at less than the minimums
  prescribed in paragraph (b) or (c) of this section, provided each
  person operating the helicopter complies with any routes or altitudes
  specifically prescribed for helicopters by the FAA

So it sounds like the FAA regulates you all the way to the ground and then it becomes a different agency jurisdiction.  I guess I just dreamed of having a helicopter, seeing something cool and landing to take a closer look. Probably can't just do that on a whim then. That's cool, I'll stick with fixed wing :)

FYI, you aren't allowed to just land a fixed wing aircraft to take a closer look, either - and it's WAY trickier to land one vertically in a field (or rather, it's really easy, but it tends to significantly damage the aircraft, the field, and you)

91.119 doesn't answer the question because the reg starts out: "Except when necessary for takeoff or landing", and this is a question specifically about landings.

This answer is correct for rural areas, you can land in the country without formality. The general case is FAA doesn't prohibit landing if the crew follows flight rules (e.g, there may be a flight path to be followed in certain areas), but FAA doesn't grant anybody the right to land everywhere either except on public use airfields. This is a matter of property owner permission. Most of land is owned by some organization, e.g. the municipality. Permission must be obtained prior to trying to land.

It all depends on the exact location. You need the Federal, State, Local, USFS, Zoning, etc... If you have a spot you'd like to land at, you need to start doing the research early and make sure you don't forget any agency or possible owner before you land. Just because the land owner says it's ok, doesn't mean you won't get into serious trouble with someone else.

What is the way to know which agencies might require approval?  Is there an online mapping system that can tell you?

@bovine unfortunately, it various by jurisdiction, and there's no one single source. best bet would be to contact a local helicopter operation in the locality in which you want to land. they are usually up on the local regs.

There is no online mapping which gathers all available restrictions.  Furthermore, some restrictions are not in law, but in policy or regulations of the agnecy (eg National Parks).  Further complicating things are zoning, which is not necessarily published but may be documented in sub-division approval. Then there are local laws, which may not be published, but may (in one case I am familiar with) be in the town board meetings minutes.  How can anyone search all these unknown sources?   The FAA claims authority over the airspace, but not on the underlying land.

There is a big warning in the lower left corner of every print/FAA digital sectional (Detroit for example) about all the places you can't land to give you a starting point. Other countries may have different rules.
Basically it works out to any place you really would like to land, unless you ask for permission that you may not get.
You can see the full details of everything I dug up for another answer here.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
How is the wind direction and wind speed measured in flight?
Most large aircraft have a wind direction and wind speed indicator. How is this measured? The vector difference between TAS and ground speed? How accurate is this?
In the below picture (taken from this question) it is displayed in the top-left corner of the top-right quadrant (just below the TAS and GS).

this question answers it more directly: http://aviation.stackexchange.com/questions/23202/how-heading-bug-is-calculated-during-cross-wind-and-tail-wind

The air-speed is measured with a "pitot-tube".

Possible duplicate of How does a pilot know if he has headwind, tailwind or crosswind?

Indirectly, as the difference between true air speed and ground speed.
Since aircraft cannot measure true air speed, several steps are needed to arrive at the correct wind speed:

The pitot tube (big aircraft have several of them) gives the stagnation pressure of the air, which is the sum of static and dynamic pressure.
The static ports (again, big aircraft have several of them) give the static pressure of the ambient air, so the dynamic pressure can be isolated.
With the static pressure and the ambient temperature the air density can be calculated.
With the density it is now possible to calculate the true air speed from the dynamic pressure.
From the compass you get the heading of the aircraft, so you know the direction of the true air speed.
The ground speed and track direction can be calculated by repeatedly measuring the location of the aircraft and dividing the distance by the time between measurements, or with modern aircraft it can be read directly from the GPS display.
Wind speed and direction can be calculated by subtracting the true air speed vector from the ground speed vector.

You will notice that there are a lot of possible sources of error in this procedure. All instruments involved have their own bias and scaling error. However, if everything is carefully calibrated and corrected, the result can be very accurate.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What is the difference between inboard and outboard engines on a Russian IL-18 turboprop?
I was looking at this picture of an Ilyushin IL-18 turboprop aircraft
Image hosted at https://i2.cdn.turner.com/cnnnext/dam/assets/160630220221-north-korea-air-koryo-il-18-nose-super-169.jpg
 and noticed that the outboard engines look significantly smaller than the inboard engines. Wikipedia lists specifications for four identical engines but the outboard cowlings don't seem to have air intakes.
Can anyone explain why?

Great question, Howard! You've got the link to your image, can you post the link that lead you there, for attribution purposes?

The inboard cowlings seem to follow a different design structure in order to make room for the landing gear compartment. The air intakes are moved aft on the outboard cowlings.

I see that now. Good answer!


text:
What are the aerodynamic differences between the nose designs of the CSeries and the Boeing 737?
The Bombardier CSeries and the Boeing 737 are two aircraft in the same class. Their nose shapes are very different from each other though as can be seen in these two images. What are the major aerodynamic differences between these two nose designs?
CSeries:

Image Source
Boeing 737:

Image Source

Note: This question and answer set don't really answer my question here because it talks about a generic nose form of aircraft made by Boeing and Airbus. I am looking for specific aerodynamic differences between nose cone shapes on specific models of Boeing and Bombardier aircraft. The Airbus part of that question cannot answer the Bombardier part of this question.
That question also does not talk about specific model as it says at the bottom:

This image is only an example and my question is not about any specific model.

I want the specifics for the nose cone shapes of Boeing 737 and the Bombardier CSeries, not specifics on the aircraft themselves. This is more like asking for for the aerodynamic difference, for example, between a blunt nose and an ogive nose than something to do with aircraft corporations.

I'm guessing that a lot of the issue here is just age. The 737 design is literally 45 years older than the C-Series. The nose of the 737 was probably designed to house very large radar equipment. On top of that advances in numerical analysis and computer assisted design allow for much better analysis of aerodynamics.

@Simon This is between Bombardier and Boeing, so it is not anything close.

This is going to be hard to answer factually. The only way to get an answer is to get a Boeing engineer and a Bombardier engineer in the same room to discuss the reasons for going with one over the other. Aside from that any answer you get is probably pure speculation or opinion.

@RonBeyer Are there any specifics on what the nose designs on these two aircraft are called? It might help more.

Did you read the top answer to the question? It exactly answers your question.  If you feel it does not, then please edit your question to be more explicit.

It's technology. The Boeing 737 nose flew first in 1957 (as the Boeing 707 nose, no less) and uses flat glass panes - curved ones were not possible back then. The Bombardier C-Series had its first flight 55 years later and uses curved window panes which follow the contour of the forward fuselage.


text:
Why is there a time range for holdover times charts?
2016-2017 FAA Holdover Time Guide
The FAA publishes holdover times for each winter season and gives a time frame for how long each type of fluid should protect the aircraft from further contamination.
Why is there a time range for these numbers?  Are there different procedures to follow if your takeoff will be before, in between or after the specified time?

I'd swear this is a duplicate, but I can't find it.

I looked at that, @ymb1, and maybe it's what I was thinking of, but that doesn't answer this question.

I'm curious, what fluid are you referring to?

@Notts90.  It doesn't matter.  Type I or IV fluid primarily.

@wbeard52 I'm not a pilot I have no idea what you mean by that, from the context, is it some sort of anti-icing fluid?

The document answers your question - Look under the table, in the section titled "Cautions:" --

 The time of protection will be shortened in heavy weather conditions. Heavy precipitation rates or high moisture content, high wind velocity, or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may be reduced when aircraft skin temperature is lower than outside air temperature.

Thus each category has a range of holdover times - longer for the most moderate conditions (barely enough snow to show up in the METAR), and shorter as conditions become more adverse.
For example if we split the difference in the "Rain on Cold Soaked Wing" category, Light Rain (-RA) would have a  holdover time around 5 minutes, Regular Rain (RA) would probably be around 3 minutes, and Heavy Rain (+RA) would wash the fluid off in 2 minutes or less.

Why is it published for a specific year? Do the numbers change each year?

@TomMcW Changes are made to the guidance each year based on additional testing or real-world experience. (A summary of changes for each year can be found in the beginning of the guide.)


text:
Does Jeppesen display runway declared distances on their charts?
I noticed that Jeppesen includes additional runway information on their 10-9 or 10-9A charts.  Are these listed values consistent with FAA runway declared distances?

No.

What does the runway distance mean under "Additional Runway Information" on Jeppesen plates?
What are Runway Declared Distances?
How do pilots use stopway, EMAS, clearway and displaced threshold?
How do runway declared distances affect my takeoff distance?

Jeppesen uses its own method to calculate additional runway information.  They have been providing additional runway information long before the FAA started providing declared distances and are fairly accurate but there is some discrepancies pilots using Jeppesen products need to be aware of.
Analysis of the two runway distance providers show Jeppesen's takeoff value is very close to the FAA's TORA value.  Jeppesen's landing beyond threshold value is the same value as the FAA's LDA value.
The two values that Jeppesen does not provide information for is TODA and ASDA.

TORA: Takeoff runway available
TODA: Takeoff distance available
ASDA: Accelerate-stop distance available
LDA: Landing distance available

It is the ASDA value that will get multi-engine pilots in trouble.  From the previous Q&As we learned that multi-engine pilots are required to ensure the airplane's accelerate-go distance is not greater than the TORA or TODA value (depending on whether or not their airplane can use a clearway for takeoff considerations) and their accelerate-stop distance must be lower than the ASDA value.
If these multi-engine pilots fail to reference applicable declared distance information they could potentially takeoff at a weight greater than allowed by their AFM and FAA regulations.
The FAA has developed a presentation talking about runway declared distances:
http://www.faa.gov/tv/?mediaId=1132

How about examples:
Lake Tahoe, CA (KTVL)

Analyze the data and you will see that if multi-engine pilots only go by the takeoff distance on Jeppesen charts they could takeoff overweight.  Jeppesen does not include ASDA values on their charts.
These pilots may conclude they can use the whole length of the runway for takeoff performance.  If their takeoff distance is the runway length they will lose the runway safety area protections designed to keep them safe.
There are many other examples.  KPIT, KSUN, KGYY, KPBI, KMIA.  Airports big and small have this issue and multi-engine pilots need to be aware of the lack of information presented to them by Jeppesen.
Stay safe!

An email from Jeppesen concerning this oversight:  After reading the email response below, it may not be a good idea to trust the runway information presented by Jeppesen.

Our Airport Diagram Charts are designed to be used for air navigation, flight procedures, and airport operations. They are not designed for aircraft performance planning. The distances contained in the Usable Lengths section of the Jeppesen Airport charts are informational and are not intended to be used for take-off and landing performance planning. These distances are provided on the charts to assist with the operational use of the runway. In order to comply with published declared distances, pilots need to reference take-off and landing performance planning data that is provided by either their own performance group, or another provider, such as Jeppesen’s OpsData service. OpsData provides on-demand runway take-off and landing performance analysis for airports worldwide, in part by analyzing, using, applying and presenting Airport Declared Distance data.
Another reason that the usable lengths are informational is that we do not revise our charts for all state source that we receive, we instead analyze that source and then revise charts based on our process criteria. What this means for the usable lengths is that we only process charts for changes in usable lengths when the change is greater than 200’. If the only change on a chart is the usable lengths and they are less than 200’, then we will make a note of the change and apply it to the chart when it is next revised sometime in a future revision. On the other hand, OpsData will update declared distances and re-run performance calculations whenever any of the lengths change by 25’ or more.
We don’t identify what the Usable Lengths should and shouldn’t be used for in the Airway Manual. Since the lengths are not intended to be used as declared distances, we have refrained from labeling them as such. That is why only some lengths are supplied and they are located under the heading ‘Usable Lengths’. The Introduction section defines the lengths we do supply and mentions that they are in regards to the physical runway length only (i.e. they don’t take into account any stopways, clearways, etc.).
AIM 4-3-6 provides the definitions of declared distances and where pilots can find them, which is the Chart Supplement (formerly the A/FD). For pilots that don’t have the availability of performance planning services, this would be where they could go to find that information.

mmm... I'd like to land at Lake Takoe, sounds tasty! ;) Otherwise, very nice answer.


text:
Can I use my non-WAAS GPS receiver with ADS-B in the United States?
I have a older style Garmin 530.  Can I use this GPS as the position source for an ADS-B installation?

I'm trying to find the FAA requirement but you must have an ADS-B certified WAAS GPS source for your ADS-B transceiver.

Garmin still offers an upgrade of the 530 to 530W. It is $3,995 for the upgrade. There will be some additional costs from the shop for replacing the antenna. The upside is that you can buy a cheaper ADS-B unit since the 530 can provide position info. https://buy.garmin.com/en-US/US/p/597181

You'll need a WAAS GPS source if you need to comply with the ADS-B mandate but there are quite a few GA pilots who only fly VFR in regions where the ADS-B mandate does not apply.
It is permissable to use a non WAAS GPS source with your transponder if you wish to voluntarily transmit ADS-B in airspace where the mandate does not apply.  The FAA and EASA seem to have gone out of their way to conceal that fact.


text:
Why did the north / south runways close at Daugherty Field (KLGB)?
The north / south runway at KLGB were recently closed.  Does anyone know the reason for the runway closures?

I'm looking at the notams and it has 12/30 closed from 09/13/2016 to 09/17/2016. The notam doesn't say why, but that its only closed from 0500 to 1315 daily for 4 days. A little more searching shows that they've been doing it in pieces since at least July, and it looks like runway maintenance/construction. On the FAA site there is a link to a "Construction Diagram" but the link is broken. Looks like they are also working on the ALS for a couple of those days.

@RonBeyer -- the querent's referring to the 16/34s not 12/30

That may make more sense, I didn't notice it because it's not notam'd out. http://www.lbflying.com/files/lbaa2008-2.pdf suggests that they have closed it because of a geometry issue. The runways were unlit, in need of repair, and not frequently used. It also added a lot of confusion to the already complex airport movement areas, so they were closed after a 2 year study.

So I did 35 hours of my flight training from this airfield in '01 and not once in 4 weeks did I hear or see of the N/S runways being used. You just bought back some fond memories of Daugherty


text:
Are there any pitfalls to be wary of when purchasing an "umbrella" insurance policy?
Typically, a pilot will have airplane insurance (or renter's insurance, if flying un-owned aircraft), car insurance, home insurance, life insurance and then for good measure purchase an "umbrella"-type insurance (usually up to $1MM). Have there been cases where this wasn't enough insurance, or the pilot thought he or she was insured but there was something unforeseen that rendered his insurance policies ineffective of shielding him or her from liability?
This question is specific towards American pilots, in this case if would be for an "average" person, owning/flying a small single-engine piston airplane and a net worth of less than $1MM.

I understand the question but I'm not sure if there's any good, general answer because it all comes down to the terms and conditions of your policy and what the circumstances of a claim are. It's difficult to say what is "enough" insurance because it depends on your other assets and the risks you can accept.

@Pondlife thanks for the question feedback. I guess I'm just wondering if there is a list (or maybe just one) common "gotcha" that there have been some examples where a pilot took what they would consider to be standard precautions with their insurance buying but it turned out not to be enough.

An umbrella policy is insurance on top of insurance in case your primary insurance is not enough. For this reason it is usually inexpensive relative to to other insurance policies.
Using your example, a million dollars beyond what you are already insured for is a pretty good amount of coverage. It would take a really catastrophic event for a small plane to do more than a million dollars worth of damage beyond the limits of an owner's or renter's insurance policy.
If you're considering an umbrella policy be sure that it does not specifically exclude aircraft because many do. If you purchase a policy through an agent who knows that you are a pilot, you're probably fine but don't assume that your commercial umbrella policy covers you because many commercial umbrella polices specifically exclude aircraft.
I would be more worried about the umbrella policy excluding aircraft (like you mentioned unforeseen things rendering the policy ineffective in the last sentence of the first paragraph) rather than a million dollars on top the normal coverage not being enough.
I'm also assuming that by typical pilot you mean small aircraft not a corporate jet or something that has a lot more potential liability.

You are correct in your assumption. I'm thinking about a typical private pilot (may have advanced ratings) who uses his/her airplane for personal travel and enjoyment.  Good point about making sure that the policy doesn't exclude aircraft or actions related to flying.

I mean it IS possible you could take out a 747 with 400 people on it and a million dollars would be a drop in the bucket but it is an unlikely scenario.


text:
What are the legal requirements for me to purchase an airplane that I will provide instruction in?
I'm planning on getting my CFI certificate and I would like to purchase a Cessna 172 to rent to students and provide instruction in.
What are the legal requirements for me to do so?  Are there specific things I need to do beyond 100 hour inspections?
What is the best way to set something like that up to provide personal liability protection?

The requirement for 100 hour inspections is probably the biggest regulatory/legal item you'll come up against.
As for other regulatory items, there's some fuzz on the subject of whether providing the aircraft used in flight instruction and receiving compensation makes that aircraft "for hire" and triggers all the other FARs that come into play when operating an aircraft "for hire" (like the requirement for a working landing light, or the requirement for approved flotation devices if you're beyond power-off gliding distance from shore).
I could argue pretty convincingly either way (and there are some convincing arguments on the internet both ways), but I've not seen anything from the FAA that I would call definitive.
The safe interpretation would be to treat the operation as "for hire" unless you can get something in writing from your local FSDO or the FAA Chief Counsel's office saying that it isn't.
(Honestly the additional regulatory burden is really not that onerous - I mean don't you want a working landing light and life jackets anyway?)

As far as liability goes you're going to want to talk to an aviation insurance broker about at least three kinds of policies:

Insurance for yourself, as a CFI.
Insurance for the aircraft, as a rental aircraft/aircraft used for instruction.
"Renter's Insurance" for your students.

The first two cover you.  The third protects your students in case they damage the aircraft on a solo flight: your insurance company may try to recoup their loss from the student responsible for the damages (subrogation), and a (good) renter's insurance policy would cover such an occurrence, as well as paying for any other things which may have been damaged like airport lighting, parked aircraft, etc.
These insurance policies may also have additional requirements above and beyond those in the FARs.
Depending on your personal assets and the level of risk you're comfortable with an umbrella liability policy - either through your aviation broker or another broker/agent - may also be something worth considering (if you have such a policy written by someone who does not specialize in aviation make certain the policy does not have an aviation exclusion).

Do you know the numbers of the FARs that come into play when operating "for hire?" Do you also need to register as a Part 91 or 135 operator?

It would fall under the definition of a commercial operator under FAR 1.1 but FAR 119.1(e)(1) specifically excepts student instruction. So you can get away without an operators certificate I believe. It would have to be under Part 61 however. Part 141 has additional requirements. The insurance, like he mentions, I believe is the most important part.


text:
If I have a float plane, can I land on any body of water?
What are the rules with regards to landing a float plane on a body of water?  Can I land anywhere (non-emergency, obviously) that would also accommodate the take-off?  If not, how do I determine which bodies of water would allow it and which would not?

Are you asking legally, or technically? If you're asking for regulations, you should specify which jurisdiction.

I'm asking about the regulations (legally) in the United States.  Whether FAA or local.  I realize there are considerations to see if you can do it technically (trees on the end, more length to take-off then land, wind, etc.) I'm just wondering if you would get in trouble from the authorities.

Ok, then I would suggest adding the faa tag, as I'm pretty sure the lba will cut your ears of if you land anywhere except a designated airfield... :)

What does ases mean here?

ASES = Airplane Single-Engine Sea.  The FAA divides stuff into categories and classes. In this case, the Category is Airplane, then the class is Single-Engine Sea.  I've seen it used to shorthand refer to "floatplane"-related stuff.  Contrasted with ASEL (airplane single-engine land) for "regular" airplane (private and single-engine commercial "land planes").

It really depends on the state, though you can't land in National Parks (the National Park Service regulates that, not the FAA).  The FAA doesn't care where you land it, though if you ball it up due to poor choice of landing area then they'll have something to say.
Some states don't really care where you land (like Oregon), others don't let you land anywhere (like New Jersey).  You should contact your state and get the regulations from them.

Any idea generally which state agency you would ask?

I'd start with the state department of transportation.  If they have a specific aviation department then they'll direct you to it.

That's not quite right. I'm sure the FAA would care if you land in a national park/forest or in a wildlife protection area.

No, the FAA wouldn't care.  The Park Service might, but the FAA wouldn't.

The FAA specifies minimum altitudes over those areas; I can't imagine they would remain uninvolved if the park service attempted some kind of enforcement.

They actually don't.  The FAA mandated minimum altitudes are specified in 91.119.  The minimum altitude over national parks is a request from the park service, and the prohibition on landing in national parks is also regulated by the park services.  See the AIM

That is perhaps technically true but likely not a legally important distinction. As I understand it, the AIM contains the request, which means it's the FAA. There are plenty of certificate action cases that refer to the AIM. It's not regulation per se, but it will be used against a pilot who ignores or violates guidelines specified in the AIM.

The AIM specifically says request and it also says it's the park/forest service that is making the request.  It's very rare that that phraseology is used.  Requests are not regulatory and never have been.  I'm aware of may certificate actions referring to the AIM, I'm not aware of a single one that refers to part of the AIM that is including a request from a separate government entity.  In fact, I'm not aware of any legal cases of any nature that are based on a statement that "requests" unless accompanied by stronger language.

@Ralgha the wording may well be because the USPS wants the right to themselves (and their contractors) to do just what they don't want the general public to do. They make a tidy penny renting out all kind of franchises in the national parks, from icecream stands to jetski rentals (and in winter snowmobile rentals) and campsites. Things that without a permit from the USPS you can't do in the parks. Were it an FAA restriction the USPS would not be able to franchise operators offering helicopter sightseeing tours for example, or floatplane charters to remote campsites.

I was soo confused what "USPS" was referring to - I wasn't sure what the Postal Service was doing renting ice cream stands. For the record, I can't find an official abbreviation but most of the time it seems to be called U.S. National Park Service

@SSumner it seems to be NPS, a la their website and stuff on info page: https://www.nps.gov/aboutus

Yeah, NPS = National Park Service, USPS = United States Postal Service. I've never seen the park service abbreviated as USPS before (they probably specifically avoid that in order to avoid confusion with the postal service.)

This is handled on jurisdiction by jurisdiction basis. While sea plane "bases" are marked on the sectional, this only means that the location has been registered with the FAA.
The air space over the water is handled federally. The water itself is handled locally. When the aircraft is on the water, it is generally considered a boat under the law, except where a jurisdiction has chosen to single out sea planes.
Unfortunately many jurisdictions have done just that. Any little mud puddle can potentially be banned for sea plane operations by the local community.
There is an association of sea plane pilots who involve themselves in advocacy to keep waters available. They publish some useful materials on this subject.
If you plan on going for your sea plane endorsement, your instructor will give you the pertinent details. If you would like to fly locally, you will need to check out your local codes. If operations have not yet been banned, it would be sensible to join the association, and take an active role in keeping local waters open to sea planes in your area.

On the water, considered a boat, there may be local speed limits which you have to take into consideration as well.

States with coastlines often manage this through a "port authority" association, like Massachuesetts.
Sometimes it is a joint association, like in the case of the PA-NY-NJ Port Authority.

According to my research. It comes down to the owner of the body of water. Please read this link as it will explain everything in detail. When it comes to landing a plane and a body of water the FAA has Little to no say. There are some inspections that have to be performed. You have to consider the zoning, other traffic, possible hazards, neighborhoods and flightpath, The amount of traffic and whether or not there is a viable airport within 5 miles. Of course it also depends on the state.
https://www.seaplanepilotsassociation.org/resources/faq/facilities-landing-areas/

Welcome to aviation.SE. Please consider putting relevant information (e.g. regulation quotes) here rather than behind a link.

Drawing on some personal observations, many float-plane sites around Seattle are marked on maps.
Kenmore
Lake Union
Rosario
But I've also observed float planes taking off and landing at sites that are not appropriately marked on the map.
I cannot cite regulations, but my eyeballs suggest that any safe place may be legally okay.


text:
Does the weight of the battery count as "fuel" in a battery powered ultralight?
14 CFR 103 compliant powered aircraft should be less than 254 pounds (excluding fuel). Do the batteries account for fuel in case of electric engine?

IMO batteries cannot be counted as 'fuel' as 'fuel' is consumed as .the flight progress. Battery does not :)

The jury (i.e. FAA) is still out on this question as of early June 2014.  FAA has indicated it will not give a gasoline "fuel allowance" to be credited against weight for batteries.  Given that fuel weighs 6 lbs. per gallon, or 30 lbs. for the maximum legal gas an ultralight can carry, it would be a somewhat negligible, but certainly welcome, allowance for would-be electric manufacturers.
One company, Chip Erwin of AeroMarine, has imported a barebones ultralight motorglider based on the Goat towed ultralight glider.  It's called the Zigolo, and carries batteries enough for 30-40 mins. of flight, without exceeding the 254-lb. weight limit of the part 103 category.
In time the FAA may well decide to grant the allowance.  It's still not going to amount to much more time, maybe 10 minutes given current battery energy density, which is a fraction of the energy density of gasoline, but research into electric storage is at a feverish pace worldwide.
Look for sport, then commercial electric aircraft, within the next 5 to 10 years.  Several electric single and two-seat electrics are already flying.  The Airbus ducted fan, recently ballyhooed as the first electric aircraft, which it certainly isn't, is a promising look at one way commercial electric applications might come to market.

Consider making a permanent account, without knowing the specifics you definitly SOUND like you can speak somewhat authoritatively on part 103... :)

No. The FAA was approached about this in 2012 and responded that there was no allowance for battery weight. All batteries must be included in the 254lb airframe weight.

Although batteries may indeed be used to provide power to an electric motor, the FAA does
  not agree that those batteries should be equated to usable fuel and excluded from an
  ultralight vehicle's empty weight.

https://rainbowaviation.company/wp-content/uploads/2017/08/elect-103-battry-def.pdf September 4, 2012

The FAA response seems lackluster since they seem to feel that any allowance of batteries equates to an unlimited allowance. That's disappointingly lacking in imagination. As such, I wonder if there is some wiggle room. Clearly, the intention is that a ULM can have as much as 7kg more than its empty mass, since it can carry fuel in addition to empty weight. There are EU self-launching gliders such as the Atos Wing and the Birdy which are 120kg, putting them just heavier than the max Part 103 empty limit, but under the 254lbs + 2.5gal of fuel and with only several minutes of endurance.

There seems to be consensus that built-in batteries count against the weight, but  removable batteries might raise questions that are unanswered to date. If it's not integral to the plane, it might be argued to fit the spirit of the rule.

This answer could be improved by adding some sources to back it up.  Welcome to Aviation.SE!


text:
Is training required under §61.55 to move from PIC to SIC?
I am current as PIC in type on a jet requiring two crew members. I will be out of currency as PIC soon and my company wants me to move to SIC position when that happens.
Am I required to have training specified under 14 CFR 61.55 for SIC if I am already type rated in the aircraft?

I can't imagine that you do, but can you be more specific about which part of 61.55 you think is in question?

I can't imagine I do either, but none of 61.55 addresses it and its vague as well.

No training needed.  If you are typed in the aircraft, none of the SIC type stuff applies (that is just an ICAO formality and is superseded by having a normal type rating).  As long as you meet the requirements to act as SIC (landing currency, company training currency, etc) you are good to transition to the right seat with no additional training.

This is an old answer, but it was linked to from another question and I realized that 61.55 isn't only for the SIC type, but 61.55(a) & (b) refer to SIC currency.  An SIC is still required to be current and it isn't clear whether a&b refer to someone who is moving from PIC to SIC and has never logged the 61.55 training.


text:
Why Pitch Trim Up/Down & Roll Left/Right switches on yoke or control stick?
My understanding is Pitch Trim should hold current Pitch position, Roll Trim should hold roll position and Rudder Trim should hold Rudder position to relieve pilot of holding the yoke/stick or pedal continuously.
But why there is Up-Down/Left-Right (Pitch/Roll) switches on yoke or stick?
Appreciate, explanation of trim fundamental with respect to this.

I mean why Pitch Trim Up or Down? and what does Up/Down signifies?

I might be mistaken, but it appears to me that you're missing an important piece on how trimming works. It's not a button you press to magically remove the control forces, but rather, you need to adjust the trim tabs (on most smaller aircraft at least, some aircraft, especially new large ones, have other mechanisms, but that's outside the 'basics' scope) to achieve the desired result.
I'll use the elevator as an example, but it applies to ailerons and rudder as well. This is a common image used when showing trim tab movement:

Basically, the trim tab extends into the airflow, pushing the elevator in the other direction. This is key though, as it's using airflow, its effectiveness diminishes when airspeed is reduced and it becomes more effective when airspeed is increased, which is exactly how the elevator itself is affected. This means that, should the airspeed change, both elevator and trim-tab will be affected the same way and the forces, and as a consequence the elevator deflection, will remain in an equilibrium. Maintaining a specific elevator deflection will cause the (aerodynamically stable) aircraft to remain at a selected angle of attack and therefore airspeed. In order to change airspeed, you need to change angle of attack, and so you need select a different elevator deflection, prompting the need to 're-trim' fairly often during a flight, especially during departure and approach. This applies to elevator trim, I've never flown with (in-flight adjustable) aileron or rudder trim, but I assume it is primarily used to counter effects of engine torque and P-factor, so it would be adjusted whenever you're changing the power setting.
You could, theoretically, skip the trimming step and hold it with arm strength, but your arms would eventually go numb and it would be virtually impossible to keep it on airspeed while accomplishing the other tasks in the cockpit during high workload periods. The March/April 2014 issue of FAA Safety Briefing talks a bit about trimming, and mentions that the Weber-Fechner law, which discusses the concept of Just-noticeable difference, states that you need about 14% of difference to the pressure you're manually holding to notice a difference, so trusting the feel of your hand pulling the yoke is not a particularly good idea. I do believe some aircraft, in particular larger ones, would require more force than humanly possible for the needed elevator deflection in certain situations, suggesting the need to use trim, but I might be mistaken on that point.
The movement of the trim tab is sometimes driven by an electric motor (or otherwise powered, hydraulics for example) in which case you have up and down buttons, and sometimes it's manual, in which case you usually have a wheel which can be rotated to pull the tabs up or down.
Up and down, which is often referred to as 'nose up' and 'nose down', signify what kind of control forces you want to remove. If you find yourself constantly pulling the nose up to maintain the desired airspeed and attitude, you'll need to apply nose up (or 'up') trim while simultaneously releasing the back pressure and vice versa. This sounds harder than it is, it just means you hold the yoke in place, and you will notice the amount of pressure needed to hold it there drops until it's completely gone. This is one of those things which is actually harder to do in a home simulator than in real life, as you'll have to move the control while applying trim. Note that the 'up' and 'down' labels do not mean the tab will move up or down, remember the tab travels in the opposite direction of the elevator, and to pull the nose up, the elevator needs to move up into the airflow, meaning the tab will actually move down, as can be seen in the picture.
As a bonus; in aircraft with no autopilot and autothrottles, if you do not apply any control forces the aircraft (aerodynamically stable) will maintain a particular airspeed. This means that for a specific configuration (flaps, landing gear, weight, power, etc) it's possible to trim the aircraft for a specific speed, this is very handy when it's crucial to maintain a specific airspeed such as during departure or approach.
This also means, which might not be obvious for someone not familiar with aircraft, that it's not possible to trim an aircraft to maintain altitude. Sure, there's usually a specific airspeed which will keep the aircraft in level flight, but that's only until you enter the next up- or downdraft, or until you've burned off a bit of fuel and aircraft has become lighter. So you will either need constant speed or power adjustments to keep it on altitude, most aircraft without autothrottles use the former.

Nice explanation.
You mean, Nose Up/Down trim switches are for correction? If pilot has to trim aircraft in pitch axis than what should he press Nose Up/Down?

@ToUsIf; Well, almost; for example if the pilot wants to go slower, you pull the nose up to increase the angle of attack (you also reduce power if you dont want to climb). If you wouldn't have trim, keeping the nose up there to fly slow would require quite a bit of force, and over time your arms will simply not be able to cope. While holding the yoke, you push to nose up trim switch (and keep it pushed) until the plane is no longer trying to rip the yoke out of your hands. Nose up/down are both for the 'pitch' axis. The directions for rudder and aileron trims are both called left/right.

The basic idea is that you adjust trim to relieve the control forces that you would otherwise have to hold.  For instance, any time that you change airspeed, the amount of air passing over the elevator changes and changes the amount of nose up/down force that it creates, requiring you to hold pressure forward or aft on the yoke in order to maintain the new airspeed.  You would then adjust the pitch trim to neutralize that force so that you don't have to hold it. Because airspeed (and therefore pitch trim) is changed so often during the flight when hand flying the aircraft, it is very convenient to be able to adjust it right on the your where you hands already are.   Not as many airplanes have aileron trim on the yoke since you don't need to change it as often, but the idea is the same.

Needing to change elevator trim is not side-effect of change of speed. Rather the elevator trim, by design, governs the airspeed (at which the aircraft will stabilize after some oscillation).

@JanHudec Both are true.  If I change speed by moving the elevator, the aircraft now needs to be trimmed if I want to maintain the new airspeed. It's kind of a chicken and egg questions.  Which comes first?  Or more appropriately, how is the aircraft being flown?  Do you fly using trim, or do you move the elevator to do what you want and then adjust the trim to maintain what you have?  I fly the second way.  :)

Consider the following scenario: You're in a 747 close to touch down and you see another airplane taxi onto the runway. You're trimmed for landing, with the engines burning about 3,000 lbs per hour each, but now you go to go to max power to go around so you're going to give each engine around 20,000 lbs per hour (from old memory so don't quote). You're going to need a lot of trim change very quickly, and that need is going to continue while you clean up the airplane.
Never heard of aileron trim on the yoke.

I don't know about other airplanes, but Learjets have "hats" on the yoke that you can push up/down/left/right for both pitch and aileron trim.


text:
Are there advantages when operating with CG near forward or aft limits?
If the center of gravity of an airplane is too far aft, it will become more unstable
Iif the CG is too far forward, then drag will increase due to increased angle of attack.
But what are the benefits to operating with the CG near the aft, or forward, CG limits? In what situations would one choose to do so?

Large aircraft typically have an optimum c.g. recommended. That c.g. is in terms of percent of mean aerodynamic chord, often expressed as %MAC. For the 747-100s and -200s, the figure is 26.6 %MAC for the zero fuel weight c.g.

A CG near the aft reduces drag by reducing the necessary downforce that has to be supplied (usually) by the tailplane.
This is also a point for competition gliding (more often than not you have water ballast in the vertical tailplane to compensate for those love handles). Aerobatic gliders sometimes feature aft lead ballast to enable maneuvers like tailspins which are not possible with a forward CG.
Aft CGs come with reduced stability, which can be a severe flight-safety concern (e.g. in case of unrecoverable spins).
Some fighter aircraft feature inherently unstable aerodynamics (see super-maneuverability) which offer great agility (e.g. turning rates), but need constant input by a flight constrol system (and woe if that fails, e.g. via Pilot Induced Oscillation).

A forward CG results in greater flight stability and reduced danger of sudden stalling, but also increased drag (because of the increased downforce required from the tailplane).  In extreme cases this can limit the maneuverability as well and cause a pancake landing (the tailplane can only produce so much lift/downforce before itself stalls, at which point it is no longer holding your nose up).

A tailplane doesn't really produce lift because it's more like an inverted wing (unless negative lift is considered lift). The further aft the CG, the less the tailplane has to push the tail down (causing drag). That's why a canard design is so much more efficient because all wings produce "positive" lift.

@PhilippeLeybaert I tweaked the answer a bit to use the term "downforce" which is what most of us in the US are used to seeing, but technically (aerodynamically) most if not all tailplanes are producing "lift" to control pitch - it's just directed downward because the airfoil is "upside-down" compared to what we're used to in a wing :-) More downforce means more (negative) lift, and thus more drag...

I stand corrected dor missing out on the negative sign,  but fortunately the drag part is correct :D

@PhilippeLeybaert: Some horizontal stabilizers are designed to generate lift or tail down force, depending on the regime of flight and the CG....  It isn't always tail down.

@LNafziger Yes, you're correct but it's almost always tail down :-) But I felt it was important to point out that the tailplane normally doesn't contribute to the total lift as it cancels out some of the lift of the main wings (reducing total lift).

@PhilippeLeybaert: I agree, but don't like comments like that to spread false rumors...  "usually" or "almost always" would be better in this case.  :)

You are right. I'll choose my words more carefully next time :-)

The tail tank is to compensate the forward shift of the cg when the wing tanks are filled. Since the wing tank volume is ahead of the wing spar, the water is slightly forward of the ideal cg position. Note that the tail tank valve is connected with the wing tank valves: When you drop the wing water, the tail tank will also be emptied to prevent a dangerous aft shift of the cg.

@PeterKämpf for large ships and/or double seaters the tank is also used solo, e.g. to compensate for more or less voluptuous crews without any water in the wings.

The main benefit of operating with an aft CG, as mentioned, is that it can measurably reduce drag. This happens because less tail down force is required to maintain level flight in a given configuration. As a result, you can burn less fuel to maintain the same speed (or increase your speed for no additional fuel burn) compared to a forward CG.
As long as you ensure you remain within your aircraft's CG envelope, you can test this out by having a passenger shift their seat aft while in cruise.
There are, of course, some safety concerns. @yankeekilo's answer covers this thoroughly, but if nothing else it should be reiterated that an aft cg is inherently less stable.
A forward CG makes recovery from stalls much easier, and in some cases can make stalls much harder to achieve because the moment-arm of your aircraft's CG changes. This change can leave the tailplane with insufficient input during slow flight, which is why you may never reach stall in the first place; it also makes landings dangerous as there may not be enough control range to flare. If this happens, you'll wheelbarrow or porpoise the aircraft.

We call that a monday-(week day of your choice) landing in German, depending on how often you hear the wheels squeak :D

@yankeekilo Hah, that's awesome.

Re "you can test this out by having a passenger shift their seat aft while in cruise."  -- what exactly can you test out by this method?  A pitch trim change?  That is obvious as to not really need testing.  A reduction in fuel consumption for a given speed or an increase in speed for a given fuel consumption--  are either of these really testable in any practical way in the real world, just by sliding one passenger's seat aft?

@quietflyer why don't you test it out in cruise

Advantages of forward CG position:

Higher stability, so less attention is needed to keep the trimmed aircraft straight and level.
If the aircraft can be made to spin, the spin is easier to end.
For taildraggers: The tail can be lifted up earlier during the take-off run.
For tricycle landing gear aircraft: Better stability on the ground.

Well, that's about it!
Advantages of rear CG position:

Less trim drag, because less downforce needs to be created at the tail and compensated by the wing.
Better maneuverability and lower control forces, because less control surface deflection is needed for the same excursion from the trimmed state.
Lower minimum speed, which translates into lower take-off and landing distances.
For taildraggers: More stability on the ground against tipping over.
For tricycle landing gear aircraft: Lower rotation speed possible at takeoff.

Note that shifting the CG more aft, behind the neutral position, will make the aircraft statically unstable and will increase trim drag again, because now the tail will operate at abnormally high lift coefficients which come with high induced drag.
The typical application for forward CG positions is a manually controlled long range aircraft which will fly in gusty weather. Then it will be beneficial to have high stability.
The typical applications for rear CG positions are performance- or maneuverability-optimized aircraft like gliders or aerobatic airplanes.


text:
What are the pros and cons of high-wing compared to low-wing design?
What are the advantages and disadvantages of a high-wing vs. low-wing aircraft design? When might one prefer one to the other?
Is the answer the same for large and small aircraft?

Related AvWeb article which is worth reading, if only for the humorous descriptions

This is actually a really hard question to answer, as there are a ton of factors. I'll try to cover a few.

Visibility is probably the reason you most hear when it comes to GA pilots.

High-wing aircraft offer better visibility below the aircraft, especially for passengers in 4-seat or larger aircraft, as the wing doesn't block it.
Low-wing aircraft can offer better visibility above the aircraft, as the wing remains mostly out of the field of view.
Note that a lot of midair collisions involve mixed types; low-wing aircraft descend into high-wing, or high-wing aircraft climb into low-wing.

Landing characteristics are different, as low-wing aircraft can incur more ground effect than high-wing.
Aerodynamic stability of the two designs differs a bit; the center of lift can be higher in a high-wing design, often offset with dihedral in low-wing aircraft.
Ground clearance (and debris protection), specifically in multi-engine aircraft, is going to be greater when engines are mounted on a high wing rather than a low wing. This is true of both propeller and jet engines, although propellers tend to have a larger radius for a given aircraft size.

There are a bunch more, but that ought to get the argument discussion going.

On the topic of visibility: when turning, high wings tend to block your view in the direction you are turning.

a lot of noise is made around flights schools regarding high-wing versus low-wing accidents but I've never seen any evidence.

@rbp Yeah, there are plenty of high+low combo accidents out on record. That's the only configuration-related accident info I've seen.

Are there advantages of high-wing in terms of aerodynamic efficiency (lift over drag)?

@Egid, your already gave really good and correct answer dealing with the most important benefits and downsides, or simple the most significant differences. I like to follow your invitation and add the differences I thought of and you have not already mentioned:
The additional ground clearance also benefits the maximum crosswind some high-wing aircraft can cope with,  what in my eyes is also an important point.
Also high wing aircraft - talking about light sports - benefit the design of the fuel system as it allows consumption from both tanks simultaneously without installation of additional fuel pumps - this is not only a benefit for lazy pilots but has probably already prevented some accidents.
Now somebody needs to tell me why I'm flying low-wing ;)

Cause low wing planes look so much cooler?  :)

I guess that's it :D

Just had a thought, are there any low wing tail draggers? Hmm, I'll ask in chat.

I guess there are some old fighter planes.

The DC-3/C-47 is a low wing tail dragger.  There are others, but they are generally 1930's era aircraft.

@Falk, your point about the light sport aircraft overlooks another benefit:  You correctly point out that no additional pumps are required.  A benefit is a lighter weight of the aircraft.  This is a very important point for LSA (Light Sport Aircraft) where the weight is limited by regulation.  This allows the LSA to carry more fuel.  Not a lot, but every bit helps.

Most taildraggers that are not of the luscombe/taylorcraft/citabria/cub/husky design are low-wings

Low wing aircraft also benefit that in a crash, much of the crash energy can go into the wings instead of into the fuselage.

Low wing aircraft have the advantage in a water landing because the wings can keep much of the fuselage above water, as well as provide a temporary staging area for deplaning passengers.  In a high aircraft, you would be lucky to get out before drowning.
Likewise, on land, low wing aircraft are easier to control in a wheels up landing.
Low wing aircraft can be designed with a more widely spaced and shorter main gear, which is more stable.  Most high wing aircraft use fuselage sponsons (MU2, ATR-42/72, Do228/328, BAe-146/Avro RJ, C-130) to house the main gear, providing a relatively narrow, and therefore, less stable track.  For those high wing designs that house the main gear in wing-mounted engine nacelles or in the wings themselves (Twin Commander, F-27/227, Dash 7/8, B-24/32), the gear must be made much longer, and therefore, much heavier.  A long main gear design is also more prone to structural failure in a hard or poorly executed crosswind landing.
Low wing aircraft are easier to refuel, and if equipped with wing-mounted engines, those would be easier to service.

Here are a couple of ground comfort related differences.
When it's hot, and you're waiting in line for fuel, or if your plane isn't hangared, you can stand in the shade under a high wing.
If you want to walk from fore of the wing to aft of the wing, to get the oil rag you forgot, with a high wing, you duck a bit and walk straight, with a low wing, you walk all the way around the wing. Twice.

My first downvote. :( I sstill think it's a good answer.

For most low wing aircraft, couldn't you climb/step on the wing? :P lol

Another factor is fuel flow (at least in small GA planes).
Lets compare a Cessna 172 to a Piper Cherokee. The Piper is low wing and requires a fuel pump (engine driven with an electric backup) to flow the gas from the wing tanks up to the engine. This add not only adds another part that can fail but the possibility that you can vapor lock the system if you run it dry. In a the Cessna (high wing) the fuel is pulled by gravity, out of the wing tanks, and into the engine much like an old car (1930's era). This eliminates the fuel pump and the vapor lock issue which some people find quite nice. At this point I am well into the habit of switching tanks every 30 minutes.
A note should be made that some Cessnas (from what I have read) do have fuel pumps now but I don't fly them so I don't know a lot about the newer model specifics.
High wing airplanes also prove to be advantageous if you are flying a lot of back country stuff. The added clearance can help you land in bushy areas or other less hospitable places where a low wing plane might strike something.
The best answer to this question can usually be found at your local airfield. Ask a guy that owns a Piper (just not a Cub), then ask a guy that owns a Cessna (just not the 400), and decide for your self based on their answers.

On the other hand, aircraft with gravity-fed fuelsystems can't fly inverted without the engine dying.

@Sean very true, for that matter most tanks are gravity fed to at least their low point (and then it may be pumped higher) making most standard fuel systems improper for inverted flight.

Another factor with low-wings is that on take off and landing, the low wing will block airflow over the empennage, reducing rudder and elevator effectiveness. That's why so many low-wings have T-tails, to keep the tail in the flow of air during landing and takeoff.

This is true not just of takeoff and landing but of any higher-AoA situation, for what it's worth.

yes! hopefully you're not flying high-AOA during other flight regimes, except for training

why is this worse with a low wing than a high wing?

because in a high wing, the airflow at high AOA is above the wing. in a low wing, the wing blocks the airflow to the tail:
http://upload.wikimedia.org/wikipedia/commons/2/24/Piper_PA-28_Cherokee_Landing_03.JPG

i know these pictures aren't perfect, but they give you an idea: http://www.airport-data.com/images/aircraft/small/000/255/255722.jpg  Here's a T-Tail arrow departing (start at 40 seconds -- https://www.youtube.com/watch?v=cbzhaSp-MEs)

Let me add one more advantage/disadvantage pair.
High-wing aircraft (at least for small GA aircraft) may be easier to preflight as wing fuel drains are more accessible and it is easier to examine the underside of the wing (flap linkages, aileron hinges, skin, possible fuel leakages). Personally, I'm tall enough to be able to see the top of the wing without a ladder, but I'll admit that this advantage shrinks for shorter pilots. The downside is ease of refueling (and sticking the fuel tanks). A Cherokee (low-wing) doesn't require a ladder to refuel whereas we carry a stepladder in our club Cessnas.

Another advantage of low wing over high wing is that I've never bashed my head on a low wing.

A quick addition to the previous answers:
Larger commercial aircraft also capitalize on the low-wing's benefits from a maintenance perspective.

Large commercial aircraft have low wings to stow away their long landing gears. Long gears make it possible to stretch the fuselage and still be able to rotate during take-off. Large high-wing aircraft with their low fuselage position are easier to load and unload, at the price that the fuselage taper has to start shortly aft of the landing gear, so no stretching is possible.

@PeterKämpf, are there advantages of high-wing in terms of lift versus drag (aerodynamic efficiency) performance?

@Jonny: The best is a mid-wing configuration. High wings have less dihedral, so less lift is lost as side force. But the difference is small. If you want to know more, why not post a new question here?


text:
What is an optimum engine-out bank angle?
I've heard three methods you should use in a multi-engine aircraft when engine-out, each recommending a different amount of bank:

Wings level, hold aileron to maintain roll and correct using rudder.
Ball centred, ailerons flush and correct using rudder.
5 degrees bank angle, hold aileron to maintain roll and correct using rudder.

Which one of these will result in the highest climb rate, and are there any advantages to other methods which don't give the best climb rate?

Gut says #3.  If I get a chance to shut one down in flight tomorrow I'll test it out.

I tested this out in the Seminole today.  My (extremely nonscientific) results are as follows:

Wings level, hold aileron to maintain roll and correct using rudder: 200 FPM
Ball centred, ailerons flush and correct using rudder: 0 FPM
5 degrees bank angle, hold aileron to maintain roll and correct using rudder: 100 FPM
2.5 degrees bank angle, hold aileron to maintain roll and correct using rudder: 200-250 FPM

At least under today's conditions*, wings level was better than 5 degrees of bank, but approximately 3 degrees of bank was slightly better than both.

Today's conditions, for the interested:

6000 MSL
-7 C
Engine shut down and feathered
About 1/4-1/2 ball deflection on all except #2
Probably about half tanks
No idea what the altimeter setting was

So it's probably a better idea to err on the side of less bank unless you need it for directional control (i.e. near VMCA). Thanks!

This will vary from plane to plane depending on design, and the best method to use for a particular airplane would be listed in the engine out procedures in the POH/AFM.
When the manufacturers are flight testing the airplanes they try various combinations and tell you the absolute best one so that you can get the best performance out of the airplane in a potentially dangerous situation.  Fly your particular airplane by the book to ensure that the airplane does what the POH says that it will do.

Examples:
The Seminole POH says:

Trim the aircraft as required and maintain a 3° to 5° bank toward the
  operating engine. The balI wiII be 1/2 to 3/4 out for minimum drag.

The Diamond Twin Star POH says:

Establish minimum / zero sideslip condition (approx. half ball towards good engine; 3° to 5° bank).

The Cessna 441 POH says:

The one engine inoperative best rate-of-climb speed at various altitudes
  is shown in Section 5. Best single-engine climb is attained with the wings
  banked approximately 3° to 4° and with a 2/3 to 3/4 ball slip into the
  operative engine when the airplane is at low airspeed and heavy weight. As
  airspeed increases and/or airplane weight is significantly reduced, the 2/3
  to 3/4 ball slip becomes less important.

I'm seeing a trend here among the light twins.  :-)
On the other hand, in the jets that I have flown, we are taught to remain wings level and center the ball with the rudder:
Here is what the Lear 60 AFM says:

Use rudder pedal force as necessary to maintain slip/skid indicator centered.

The Falcon 50 AFM doesn't mention it at all.
This isn't the case for all jets though.  The A320 Flight Crew Training Manual says:

ENGINE FAILURE
In flight, if an engine failure occurs, and no input is applied on the
  sidestick, lateral normal law controls the natural tendency of the
  aircraft to roll and yaw. If no input is applied on the sidestick, the
  aircraft will reach an approximate 5 ˚ constant bank angle, a constant
  sideslip, and a slowly-diverging heading rate. The lateral behavior of
  aircraft is safe.
However, the PF is best suited to adapt the lateral trimming
  technique, when necessary. From a performance standpoint, the most
  effective flying technique, in the event of an engine failure at
  takeoff, is to fly a constant heading with roll surfaces retracted.
  This technique dictates the amount of rudder that is required, and the
  resulting residual sideslip.
As a result, to indicate the amount of rudder that is required to
  correctly fly with an engine-out at takeoff, the measured sideslip
  index is shifted on the PFD by the computed, residual-sideslip value.
  This index appears in blue, instead of in yellow, and is referred to
  as the beta target. If the rudder pedal is pressed to center the beta
  target index, the PF will fly with the residual slip, as required by
  the engine-out condition. Therefore, the aircraft will fly at a
  constant heading with ailerons and spoilers close to neutral position.

I'll add a physical explanation (based on the excellent How It Flies):
The thrust asymmetry generates a torque that will tend to turn the aircraft. To avoid turning, you counter this torque with rudder. The moment of the rudder will balance the moment of the thrust, but the force generated by the rudder will not be balanced and will cause some slip itself and slip increases drag. So you need to balance the force by adding a bit of sideways lift by banking into the live engine ("raise the dead").
The amount of bank depends on the relative magnitude of the moments and forces involved. If the engines are further apart, the moment of thrust will be larger so rudder will have to produce larger force to counter it and the bank will have to be higher to counter the rudder force. The further aft the rudder is, the less force it needs to produce to yield the same moment and therefore less bank will be needed.
It follows that the correct bank angle is different for each aircraft. See Lnafziger's answer for examples.
Note that the slip-skid ball will no longer correspond to slip directly. The ball shows the direction of total weight (gravity plus centrifugal force). Normally it is centred when the weight is correctly balanced by lift, but here the lift is additionally balancing the rudder force, so the ball will be slightly off centre as the weight is directly to the ground when flying straight, but the aircraft is slightly banked.

3-5 degrees bank angle ("raise the dead"). Use the rudder to keep the skid/slip about half a ball off. That's the standard operating procedure for best performance.